Process of tanning hides.



UNITED STATES PATENT OFFICE.

GEORGE S. 'KIMBALL, OF CAMDEN, ARKANSAS, ASSIGNOR TO MICHAEL W. BORDERS. OF CHICAGO, ILLINOIS.

PROCESS OF TANNING HIDES.

No Drawing.

Specification of Letters Patent.

Patented Feb. 10,1914.

To all whom it may (Once/'11.

Be it known that I, Gnoncn S. KIMBALL. a citizen of the United States, residing at Camden. in the county of Ouachita and State of Arkansas, have invented a certain new and useful Improvement in Improved Processes of Tanning Hides, of which the following is a full, clear, and exact description.

This invention relates to a process of tanning hides.

The object of the invention is to provide an improved and simplified process of tanning hides, whereby a large saving, both in time and money, may be effected, as com pared with methods now in general use.

This application is intended to replace my application No. 428.939, filed April 24, 1908.

In the practice of my improved process, the hides are first pickled, substantially in the usual Way, and are then immersed in a bath consisting of a liquor such as is produced by the destructive distillation of a particular kind of lignite of the cretaceous age or period, until properly tanned. The duration of the immersion will vary with different hides. but skilled operators can readily ascertain by examination when the process is completed. In the case of sheep skins, it has been found, in practice, that hides can be properly and thoroughly tanned by an immersion of about twelve days. hen the tanning process is completed, the hides are removed from the liquor and subjected to any Well known or desired linishing process.

While I have hereinbefore designated the substance from which the liquor used in the practice of my improved process is obtained as lignite of the cretaceous age or period, not all cretaceous li nites yield a liquor possessing the essential tanning quali- -ties of that which I employ and have herein described. So far as I am aware, or have been able to ascertain from an exhaustive examination of various treatises on geology and mineralogy and of Government and State geological and mineralogical reports, the lignite from which the tanning liquor used in my improved process is produced has no distinctive name which will serve to differentiate it from other lignites. So far as appears, therefore, the only manner of identifying said lignites is to define the locality in which they occur. So far as I 3 am now aware, said lignites occur and are produced only in a somewhat restricted district or area which includes several counties in the State of Arkansas, including the county of Ouachita in said State, and are those'referred to in the'following extract from a work known as The Jlt'nerais and Rocks of il'riransas, by F. L. Harvey, B. S, p. 28 (published in 1886) Brown coal occurs extensively in the recent formations of the south and east parts of the State (Arkansas). The beds are from a few inches to over four feet thick. They ha ve been examined in Greene, Ouachita and other counties and. found to be of fair quality, yielding a high per cent, of volatiie matter. \Vhcther they are adapted for manufacturing illuminating gas and coke is an open question. The most. of the coal is structureless and crumbles on exposure, but some shows the woody structure and is then called lignite.

For purposes of convenient reference, I will hereinafter refer to the particular lignite from which the tanning liquor which I use in my improved process is produced as Ouachita lignite. The tanning liquor is obtained by the destructive distillation of the lignite for a period of from 7 to 10 hours at temperatures of from 300 degrees to 450 degrees Fahrenheit and may be performed in any usual form of retort for effecting destructive distillation. The distillate consists, principally, of two distinct products, to wit; a watery liquor and an oil, which separate by gravity, the watery liquor being the heavier and soon settling when the full liquor is allowed to stand, so that it can be readily drawn off from the oil. The Watery distillate produced from the destructive distillation of the panticular lignite specified is characterized by the fact that it carries in solution certain of the higher phenols, and it is believed that the tanning properties of the liquor are due to the oxidation products of these phenols.

In the practice of my process, the liquor is used full strength, as produced, withoutdi lotion or change of any kind. Also, while I prefer to use the watery distillate alone, its tanning action is-not appreciably afiected by the presence of the oil and, if desired, the full liquor may be used in the practice of imy improved process, the presenceof the oily distillate, which is almost black in color, operatin to impart a dark. color and a highly p enolic odor to the leather, due to thepresence of insoluble phenols. l have also discovered that a liquor which, as re gards its tanning properties and characteristics, is the substantial equivalent of the original Watery distillate may be produced from the oily distillate by treating the same with a weak alkaline solution, as a saturated lime Water solution, a. S'per cent. solution of carbonate of soda, or a EZ-per cent. solution of caustic soda, in the following manner: A quantity of the alkaline solution equal to from one-half to two-thirds of the quantity of the oily distillate to be treated is added to the oily distillate and the mixture is agritated, as by stirring, for a period of about one hour. The alkaline solution operates to dissolve the phenols remaining in the oil and, being heavier than the oil. soon settles when allowed to stand and may be drawn off, all substantially as in the ease of the original Watery distillate. Said solution. after being drawn off, is neutralized by the addition of acid, when it is ready for use in connection with my improved tanning process, said liquor being used in the same manner as the original watery distillate. the case of the original Watery distillate. the tanning action of the liquor produced by treating the oil distillate with an alkaline solution is due to the presence, in solution. of

certain higher phenols.

I clain1:

1. The process 01" tanning hides which con sists in first preparing the hides in any usual manner and in then soaking tneni in liquor containing higher phenols in solution such as are found in the watery distillate of Oua chita lignite produced by distillation thereof at temperatures of from 300 degrees to 450 degrees Fahrenheit, substantially as described.

The process of tanning hides which consists in first preparing the hides in any usual manner and in then soaking them in liquor such as is produced by the destructive distillation of Ouachita cretaceous lignite, substantially as described.

3. The process of tanning hides which consists in first preparing the hides in any usual manner and in then soaking them in liquor such as is produced by the destructive distillation of Ouachita lignite effected at a temperature of from 300 to 4430 degrees Fahrenheit, substantially as described.

4. The proct. of tanning hides which consists in first preparing the hides in any usual manner and in then making them in the Watery portions of the liquor produced by the destructive distillation of Ouachita Cretaceous lignite. ubstantially a described.

3. The process of tanning hidewhich consists in first preparing the hide in any usual manner and in then soaking them in the watery portions of the liquor produced by the de lliI'llYQ d illation of Ouachita cretaeeous gnu-e eli'et ed at temperature of from 300 degrees to 1 degru-s Fahreir heit, substantially as described.

In te. iniony whereof, I hereunto ailix my signature in the presence of two witnesses.

GEO. s. iuunilL-L.

'itnes: es I M. E. MCGUIRE, .Finuixnn J. Loxo. 

